The fossil chrysophyte stomatocyst flora of six peat samples from Glacier Ampère, a retreating glacier on Grand Terre, in the subantarctic Kerguelen Archipelago, has been investigated by means of scanning electron microscopy. Thirty-two different stomatocysts were recorded, 27 of which appeared to be previously undescribed. This paper contains the descriptions and illustrations of the new morphotypes. This is the first systematic study of chrysophyte stomatocysts from this subantarctic archipelago following the guidelines of the International Statospore Working Group.
2 heterotrichous and 9 hypotrichous ciliates including one new genus collected from the Yellow Sea and the Bohai Bay, north-eastern China are morphologically investigated based on living observations and using various silver impregnation methods: Protocruzia contraxMansfeld, 1923; Condylostoma magnumSpiegel, 1926; Holosticha mancaKahl, 1932; Oxytricha saltans (Cohn, 1866); Hemigastrostyla enigmatica (Dragesco & Dragesco-Kernéis, 1986) nov. gen., nov. comb.; Uronychia setigeraCalkins, 1902; Uronychia binucleataYoung, 1922; Uronychia transfuga (Müller, 1786); Euplotes minutaYocum, 1930; Aspidisca steini (Buddenbrock, 1920); Aspidisca leptaspisFresenius, 1865. Morphological characteristics and taxonomic position of all known Uronychia-species are briefly compared and discussed. About 3 Protocruzia-, 5 Uronychia- and 12 Aspidisca-species are considered as junior synonyms according to the results of our current studies. The hypotrich, Hemigastrostyla nov. gen., might be assigned to the family Oxytrichidae. Diagnosis of this new genus: body slightly cephalized; mostly 8–10 frontal, 5 ventral and a few extra lateroventral cirri which possibly derive from the 6th (right-most) cirral anlage during morphogenesis; caudal cirri present. Marine or brackish water forms. It is recognised from other oxytrichids by the cephalized body shape and possessing extra lateroventral cirri right to the transverse ones.
The oxymonad flagellate Monocercomonoides termitisRadek, 1994, an intestinal symbiont of the dry-wood termite Kalotermes sinaicus, is renamed M. hausmanni nom. nov. because of preoccupation by M. termitisKrishnamurthy & Sultana, 1979.
The phylogeny of representative species of the apicomplexan order Haemosporina Danilewsky, 1885 was reconstructed by cladistic analysis. Life cycle and ultrastructural characters for members of the genera Plasmodium, Haemoproteus, Leucocytozoon, Hepatocystis, and Polychromophilus were assessed using Eimeria tenella as an outgroup. Each of these genera was monophyletic and a clade containing Haemoproteus, Hepatocystis, and Polychromophilus was the sister group to Plasmodium. There was no obvious correlation between the parasite phylogeny and that of the vertebrate hosts. There was however, a general agreement between the parasite phylogeny and that of the dipteran hosts. There was no pattern of strict cospeciation between parasites and these overall host groups, but there appears to be more evidence of coevolution of parasites with their vectors than with their vertebrate hosts. This correspondence is indicative of a more ancient parasite-vector association.
Distinct homogeneous clusters of established diatom taxa are described as three new genera. Only the nomenclatural type of the first genus, Frankophila similioides, is introduced as a new species. Two other species, F. loetschertii and F. maillardii belong to this genus with a unique complex of characteristic features of the Fragilariaceae, in particular of the sub-genus Staurosira, and of naviculoid Raphideae. Actually 13 taxa of Navicula sensu late belong to Mayamaea with M. atomus as type species: whereas Navicula pelliculosa, Navicula saprophila and Navicula iranensis are transferred to Fistulifera. In addition to these proposals Stauroneis spicula is transferred from the actually used combination Navicula spicula to the genus Haslea SIMONSEN.
The extrachromosomal nucleolar apparatus in the macronucleus (Ma) of the ciliate Paramecium putrinum was studied by LM cytochemistry, confocal microscopy and EM. The nucleoli vary in size and number. Three main types of nucleoli can be distinguished: small compact ones, vacuolated and large “composite” nucleoli (CN). The CN are often flattened at the Ma surface, but no blebbing or nucleolar extrusion was observed with EM. The CN are composed of several “nucleolar units” represented by a ring of dense fibro-granular material with an electron dense body in the centre. The nucleolar units are embedded in loose fibro-granular material. Ag-NOR staining and EM data provide evidence for the location of nucleolus organizer regions (NORs) at the CN periphery in the perinucleolar chromatin. Ag-NOR staining reveals a network, connecting extrachromosomal NORs with each other and possibly presenting a skeleton for continuous strands of nucleolar material observed by confocal microscopy during certain stages of cell cycle. “Free” NORs are scattered through the Ma.
During conjugation of Blepharisma, only some micronuclei enter meiosis. Other micronuclei, called somatomicronuclei, do not degenerate but differentiate directly into macronuclear anlagen (secondary anlagen) without meiosis and karyogamy. Normal (primary) anlagen develop from synkaryon derivatives. We observed these processes at the ultrastructural level.In early conjugation (0-2 hours after pair formation), all micronuclei swell. This correlates with decondensation of the micronuclear chromatin. At 3 hours, the micronuclei differentiate into somatic and meiotic (leptotene) ones: the latter develop bundles of microtubules. The somatomicronuclei remain homogeneous and lack microtubules. At 8-9 hours meiotic micronuclei display synaptonemal complexes and thus are in pachytene; at the same time, structures in form of loose chromatin patches first appear in somatomicronuclei. The patches gradually condense and become conspicuous at 10-12 hours (stages from diplotene to metaphase I of meiosis). At about 12 hours, the meiotic micronuclei are in metaphase I and display acentric intranuclear spindles with blunt poles and homogenous polar caps; the bivalents have prominent kinetochores. At 16 hours, the somatomicronuclei contain numerous chromatin patches which are possibly subchromosomes, and first nucleoli appear in them. At 16-18 hours, the stage of pronuclei is reached; and other meiotic products start degenerating. The migratory pronuclei show concentration of the chromatin at the centre of the nucleus. At 20, 26, 28 and 34 hours, the fine structure of somatomicronuclei (secondary anlagen) changes little. Their size remains constant (about 5-6 mu m) However the nucleoli enlarge at 34 hours. The first division of the synkaryon has protruding poles and no polar caps, unlike meiosis I; though, the nuclear envelope remains intact even at the poles. The synkaryon divisions give rise to new micronuclei and primary macronuclear anlagen.The primary (meiotic) macronuclear anlagen differentiate in number of 2-4 at 22-24 hours. They are much larger than secondary anlagen (up to 20 mu m) and, at early stages of development, their chromatin is so strongly decondensed that the anlagen look "empty". However later (by 34 hours) loose chromatin patches, small bodies of condensed chromatin and nucleolar primordia appear in them, like in somatomicronuclei, and the primary anlagen at 34 hours show additionally a karyosome-like central condensation of the chromatin.
The macronucleus of vegetative cells of Blepharisma japonicum contains numerous discrete chromatin bodies and nucleoli of the compact type. The nucleoli contain very dense inclusions likely to be the dense fibrillar component of the nucleoli themselves. The macronuclear envelope displays tightly packed pore complexes. Until the 10th hour of conjugation, the old macronucleus shows the same fine structure as in vegetative cells. At 12 hours (approximately during metaphase I), the fibrillar and granular parts of the nucleoli segregate and the latter gradually disappear. At 14 hours, all nucleoli are reduced to their fibrillar parts that have the aspect of small dense bodies scattered in the nucleus. Simultaneously, the chromatin bodies begin to unite into a common network. This process continues at 16 hours (stage of pronuclei). The chromatin network is connected to the nuclear envelope via submembrane bodies of condensed chromatin tightly applied to the inner nuclear membrane. The macronuclear envelope has no coating of dense material in these areas. Thereafter (24 and 26 hours), areas of nuclear matrix free of the chromatin network appear in the macronucleus. At 28 and 34 hours, the chromatin network condenses and the residual nucleoli are caught in its meshes, being incorporated into the chromatin. The points of contact of the network with the nuclear envelope become less numerous.
The morphology and ecology of some strobilidiine ciliates from brackish water basins adjacent to the North Sea of Germany (Dithmarscher and Beltringharder Koog) were investigated using Lugol fixed material, life observation and protargol impregnation. Two species are redescribed: Rimostrombidium caudatum (Kahl, 1932) nov. comb. and R. conicum (Kahl, 1932), For these species neotype specimens are designated. Rimostrombidium veniliae (Montagnes & Taylor, 1994) was recorded from this area for the first time and is briefly described. The ecological data comprise the abundance at different grades of salinity and temperature, seasonal occurrence and content of food vacuoles.
Light and electron microscopical observations have been made on the gonyaulacoid dinoflagellate Protoceratium reficulatum (Claparède et Lachmann) Bütschli collected close to the type locality of Protoceratium acerosBergh, the type species of Protoceratium. Analysis of plate tabulation shows agreement with Gonyaulax grindleyiREINECKE and supports conspecificity between P. reticulatum, P. aceros and G. grindleyi, the first name having priority. The ultrastructure includes a branched chloroplast and a centrally located pyrenoid complex. The pusular system consists of one or two sac pusules associated with the flagellar canals. The three-dimensional arrangement of the flagellar apparatus is basically similar to that of other dinoflagellates except for the presence of a single microtubular root associated with the longitudinal basal body. Each flagellar canal is surrounded by a distinct striated fibrous collar. The collars are interconnected by two striated connectives. The plate tabulation and fine structure of Protoceratium reficulatum indicate close relationship to the genus Gonyaulax, with minor differences in plate tabulation and fine structure. It is suggested to maintain the genus Protoceratium until the fine structural diversity with Gonyaulax is better known.
Victoriniella multiformis gen. et sp. nov. is a polymorphic parasitoid of uncertain taxonomic position that infects the marine centric diatom Coscinodiscus wailesii. Motile trophozoites attached to the diatom protoplast by means of a pseudopodium which was also used for incorporation of host cytoplasm. At the end of the trophic phase several filose pseudopodia were frequently formed which were used for locomotion. Thereafter, two divisions frequently followed, and led to the formation of cone-shaped cells of characteristic shape which left the empty frustule. Among the offspring two forms of motile stages were observed: Cells of type A were free-swimming and possessed two anterior inserted flagella, whereas cells of type B did not swim but moved by means of two contractile filopodia. Occasionally, cyst formation was observed inside infected diatoms.
